Mimecast has launched limited-edition packaging and migration services aimed at Symantec's customers.
The trial from the security specialist directly targets customers of Symantec's MessageLabs email security.
The package includes free email security risk assessments, in order for organisations to "see first-hand the limitations of their incumbent email security system".
The offer for current Symantec customers runs until 30 November 2019.
Mimecast claims that the main reason Symantec customers may be considering jumping ship is due to uncertainty about whether "MessageLabs will be able to effectively ensure email security without the costly development and innovation it takes to keep pace in an ever-evolving threat landscape".
Symantec has struggled in recent years to transform from a legacy firewall vendor to a cloud security specialist.
Last month, it agreed to flog its enterprise division to Broadcom for $10.7bn (£8.6bn) and just last week the Wall Street Journal reported that a pair of private equity firms had approached it to buy the consumer business for over $16bn.
Earlier this year, Greg Clark stood down as CEO after a dismal Q4 report and was replaced by Richard Hill, a former chief exec at semiconductor manufacturer Novellus Systems.
Prior to agreeing to the Broadcom deal, Symantec announced restructuring plans that will see it slash seven per cent of its global headcount and downsize, vacate or close some of its facilities. This strategy is expected to complete in its fiscal 2020.
"Mimecast has already easily transitioned more than 3,800 organisations from the Symantec on-premise and cloud-based email security systems," said Neil Senior, VP of global customer success at Mimecast.
"We're ready to talk to customers who are concerned about the impact of their email security provider announcing $1bn-plus cuts in expenses including research and development, sales and support."
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